Backlight device

Details Backlight device Backlight device

2002-03-29

2003-03-04

Tso, Laura K. (Department: 2875)

Illumination

Plural light sources

With support

C362S225000, C362S033000

Reexamination Certificate

active

06527414

ABSTRACT:

This application claims the benefit of the Korean Application Nos. P2001-16475 filed in Korea on Mar. 29, 2001, and P2001-43385 filed in Korea on Jul. 19, 2001, which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a backlight device, and more particularly, to a backlight device for a liquid crystal display.
2. Background of the Related Art
In general, liquid crystal display (LCD) devices are used as display screens in a wide variety of applications including notebook computers, monitors, space crafts, and aircraft, for example. Presently, thin profile LCD devices have a display screen of not more than a few centimeters.
Currently, LCD devices use a backlight device as a light source that is disposed on a rear portion of an LCD panel. In general, the backlight device is a cylindrical fluorescent lamp usually arranged as one of a beneath-type or a light plate-type. However, the backlight device is not efficient in consideration of thickness, weight, and power consumption.
The beneath-type backlight device is limited in its fabrication since a gap must be maintained between the lamp and the LCD panel to provide of a light diffusing means for uniform distribution of light. Moreover, as the size of display panels increases, an increase in a light emission surface area of the backlight device is required. Accordingly, if a relatively large beneath-type backlight device is fabricated, the light emission surface may not be uniformly smooth to provide the light diffusing means of an adequate thickness.
The light plate-type backlight device includes the fluorescent lamp disposed along a circumference thereof, and a light plate is used for diffusing the light emitted from the fluorescent lamp. Since the fluorescent lamp is disposed along a circumference of the light plate-type backlight device, the amount of light transmitted through the light plate is low. Accordingly, expensive optical design and fabrication technologies are required for the light plate-type backlight device in order to provide uniform distribution of light.
Accordingly, the beneath-type and light plate-type backlight devices each have their own unique disadvantages. The beneath-type backlight device is commonly used in LCD devices, wherein display brightness is more important than a thickness of the display screen. The light plate-type backlight device is commonly used in portable LCD devices, wherein a thickness of the display screen is more important than display brightness.
FIG. 1
shows a perspective view of a related art beneath-type backlight device for an LCD according to the related art, and
FIG. 2
shows a power line connected between a light emission lamp and a connector according to the related art. In
FIG. 1
, the backlight device is provided with a plurality of light emitting lamps
1
, an outside case
3
for fastening and holding the light emitting lamps
1
, optical diffusing means
5
a
,
5
b
, and
5
c
arranged between the light emitting lamps
1
and the LCD panel (not shown), and a reflecting plate
7
. The reflecting plate
7
is disposed on an inside surface of the outside case
3
for focusing the light emitted from the light emitting lamp
1
onto a display part of the LCD panel, thereby increasing a light utilization efficiency. The backlight device includes the optical diffusing means
5
a
,
5
b
, or
5
c
for preventing portions of the light emitting lamp from being displayed on a display surface of the LCD panel, thereby providing a light source having a uniform light distribution.
In
FIG. 2
, the light emitting lamp
1
, commonly referred to as a cold cathode fluorescent lamp (CCFL), has electrodes
2
and
2
a
disposed at opposing ends inside of a fluorescent tube for emitting light when a power is applied to the electrodes. Both ends of the light emitting lamp
1
are inserted into recesses formed along opposing surfaces of the outside case
3
. The light emitting lamp
1
includes power lines
9
and
9
a
that each include a first end connected to the electrodes
2
and
2
a
of the light emitting lamp
1
and a second end connected to a separate connector
11
that is connected to a driving circuit (not shown). The power lines
9
and
9
a
are bent to a lower part of the outside case
3
and connected to the connector
11
.
However, the backlight device according to the related art has a complicated wiring scheme since the connector that connects the power line to a driving circuit is required for every light emitting lamp. Accordingly, since the power lines are bent and must be individually connected to the connector, fabrication efficiency is decreased. Moreover, since each of the power lines must be inserted into a through hole in the outside case, fabrication efficiency is decreased and any future maintenance of the light emitting lamp is time consuming and costly.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a backlight device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a backlight device that increases working efficiency and fabrication productivity, and can be easily maintained.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a backlight device includes a plurality of light emitting lamps, a plurality of upper and lower holders each having a plurality of recesses for receiving the plurality of light emitting lamps, a plurality of conductive layers for supplying power to the light emitting lamps, and light diffusion means disposed over the plurality of upper holders.
In another aspect, a backlight device includes a plurality of light emitting lamps, each of the lamps having a first length corresponding to opposing end portions of the light emitting lamps, a plurality of lower holders arranged at a first distance away from each other corresponding to approximately the first length, each of the plurality of lower holders having a plurality of recesses for receiving lower surfaces of the opposing end portions of the plurality of light emitting lamps, a plurality of upper holders arranged at the first distance away from each other, each of the plurality of upper holders having a plurality of recesses for receiving upper surfaces of the opposing end portions of the plurality of light emitting lamps, and a plurality of conductive layers formed on opposing surfaces of each of the plurality of lower and upper holders for supplying power to the plurality of light emitting lamps.
In another aspect, a backlight device includes a plurality of light emitting lamps, each of the lamps having a first length corresponding to opposing end portions of the light emitting lamps, a plurality of lower holders arranged at a first distance away from each other corresponding to approximately the first length, each of the plurality of lower holders having a plurality of recesses for receiving lower surfaces of the opposing end portions of the plurality of light emitting lamps, a plurality of lower supporting parts formed between the plurality of lower holders for supporting the plurality of lower holders, a plurality of upper holders arranged at the first distance away from each other, each of the plurality of upper holders having a plurality of recesses for receiving upper surfaces of the opposing end portions of the plurality of light emitting lamps, and a plurality of conductive layers formed on opposing surfaces of each of the plurality of lower and upper holders for supplying power to th

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